I am very sorry to say that that there is no research that supports this idea that coral calcium cures cancer. This unsupported relationship between coral calcium and cancer is the primary reason the Federal Trade Commission (FTC) has filed charges and sent dozens of warning letters to Web site operators for making false and unsubstantiated claims about coral calcium and cancer.
Promoters say that taking coral calcium supplements changes the pH of cells towards the alkaline range, and that since cancer cells can't survive in an alkaline environment, they die off, "curing" cancer.
The research on coral calcium and cancer suggests that taking coral calcium may change the pH of your bodily fluids. However, cells, like your blood, maintain a neutral pH. They have to keep the same pH level, otherwise your body wouldn't work properly.
Nothing you eat, whether food or supplement, will change how acidic your cells or your bloodstream are.
Based on reviewing the available research on coral calcium and cancer, I believe that taking coral calcium supplements, as part of a healthy lifestyle, combined with diet and exercise, may be helpful in preventing cancer. One study has suggested that calcium can help prevent colon cancer. However, there is no evidence that coral calcium cures cancer.
Good luck and best wishes.